Cyclohexane is currently produced using a liquid phase benzene hydrogenation reactor. As the hydrogenation reaction is quite exothermic, heat must be continuously removed from the system. Heat removal is primarily effected via a pump-around loop, via which withdrawn reactor liquid phase is continuously moved through a heat exchanger in which it is cooled. The heat exchanger often operates to produce low pressure steam. The cooled liquid is returned to the hydrogenation reactor. Fresh catalyst may be added to this cooled liquid prior to reintroduction into the hydrogenation reactor.
Undesirably, the catalyst may gradually plate out on the heat exchanger, resulting in reduced performance of the heat exchanger, and eventually a need to shut the plant down. The decrease in run life and concomitant increase in the number of turnarounds is uneconomical and detrimental to the overall unit economics.
An ongoing need thus exists for a system and process that reduce or eliminate heat exchanger fouling during the hydrogenation of aromatic hydrocarbon(s), and/or allow for cleaning of the heat exchanger without halting production.